Bump up version for 4.3 candidate.

NOTRY=true
TBR=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/948003002

Cr-Commit-Position: refs/heads/master@{#26798}

src/version.cc

@@ -10,7 +10,7 @@
 // NOTE these macros are used by some of the tool scripts and the build
 // system so their names cannot be changed without changing the scripts.
 #define MAJOR_VERSION     4
-#define MINOR_VERSION     2
+#define MINOR_VERSION     3
 #define BUILD_NUMBER      0
 #define PATCH_LEVEL       0
 // Use 1 for candidates and 0 otherwise.